Sodium naphthalene-2-carboxylate

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Testing was conducted between 16 May 2008 and 13 June 2008.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The work described was performed in compliance with UK GLP standards (Schedule 1, Good Laboratory Practice Regulations 1999 (SI 1999/3106 as amended by SI 2004/0994)).

Type of method:

flask method

Test material

Test material information

Constituent 1

Reference substance name:

Sodium naphthalene-2-carboxylate

EC Number:

700-038-4

Cas Number:

17273-79-9

Molecular formula:

C11 H7 Na O2

IUPAC Name:

Sodium naphthalene-2-carboxylate

Results and discussion

Water solubility

Water solubility:

86.5 g/L

Temp.:

20 °C

pH:

ca. 7.6

Any other information on results incl. tables

                  Preliminary test

Observations, concentrations and pH relating to the samples are shown in the following table:

Sample	Concentration (% w/w)	Observation	pH
1	10.0	Clear, colourless solution, with a slight excess of undissolved test material.	8.1
2	20.1	Clear, colourless solution, with much excess undissolved test material.	7.8
3	30.0	Hazy liquid, but more excess undissolved test material.	7.8
4	39.9	Hazy liquid, but more excess undissolved test material.	7.9
5	60.0	Dampened test material only.	*

* not measured due to the nature of the sample

The preliminary estimate of water solubility was approximately 10 % w/w of solution.

Definitive test

The absorbances relating to the standard and sample solutions are shown in the following table:

Solution	Absorbance
Standard 26.3 mg/l	0.793
Standard 25.4 mg/l	0.766
Matrix blank	None detected
Sample 1A	1.057
Sample 1B	1.065
Sample 3A	1.030
Sample 3B	1.027

The concentration (g/l) of test material in the sample solutions is shown in the following table:

Sample Number	Time Shaken at ~ 30ºC (hours)	Time Equilibrated at 20ºC (hours)	Concentration (g/l)	Solution pH
1	24	24	87.9	7.6
3	72	24	85.2	7.6

Mean concentration:     86.5 g/l at 20.0 ± 0.5ºC
Range:                          85.2 to 87.9 g/l

Validation

The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 0 to 50 mg/l.  This was satisfactory with a correlation coefficient of 0.999 being obtained.

Discussion

Sample 2 was lost when the centrifuge tube broke whilst the sample was being centrifuged. However, the results for Samples 1 and 3 indicate that solution saturation was attained after 24 hours shaking. Therefore, calculating the water solubility as the mean of Samples 1 and 3 was considered valid.

Conclusion

The water solubility of the test material has been determined to be 86.5 g/l of solution at 20.0 ± 0.5°C.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): very soluble (> 10000 mg/L)
The water solubility of the test material has been determined to be 86.5 g/l of solution at 20.0 ± 0.5°C.

Executive summary:

For substance Na-Na in project number 1307-0436 the water solubility of the test material has been determined to be 86.5 g/l of solution at 20.0 ± 0.5°C by using the flask method, Method A6 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).